title: Growth, clonability, and radiation resistance of esophageal carcinoma-derived stem-like cells.
abstract: OBJECTIVE
  To separate/enrich tumor stem-like cells from the human esophageal carcinoma cell line OE-19 by using serum-free suspension culture and to identify their biological characteristics and radiation resistance.
  
  
  METHODS
  OE-19 cells were cultivated using adherent and suspension culture methods. The tumor stem-like phenotype of CD44 expression was detected using flow cytometry. We examined growth characteristics, cloning capacity in soft agar, and radiation resistance of 2 groups of cells.
  
  
  RESULTS
  Suspended cells in serum-free medium formed spheres that were enriched for CD44 expression. CD44 was expressed in 62.5% of suspended cells, but only in 11.7% of adherent cells. The suspended cells had greater capacity for proliferation and colony formation in soft agar than the adherent cells. When the suspended and adherent cells were irradiated at 5 Gy, 10 Gy, or 15 Gy, the proportion of CD44+ suspended cells strongly and weakly positive for CD44 was 77.8%, 66.5%, 57.5%; and 21.7%, 31.6%, 41.4%, respectively. In contrast, the proportion of CD44+ adherent cells strongly positive for CD44 was 18.9%, 14.%, and 9.95%, respectively. When the irradiation dose was increased to 30 Gy, the survival of the suspended and adherent cells was significantly reduced, and viable CD44+ cells were not detected.
  
  
  CONCLUSIONS
  Suspended cell spheres generated from OE-19 esophageal carcinoma cells in serum-free stem medium are enriched in tumor stem-like cells. CD44 may be a marker for these cells.
authors.affiliation: Provincial Clinical College of Fujian Medical University, Fujian Provincial Tumor Hospital, Fuzhou, Fujian, China E-mail : Jianchengli6@126.com.
authors.forename: Jian-Cheng
authors.initials: JC
authors.lastname: Li
authors.forename: Di
authors.initials: D
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Yang
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Wang
authors.forename: Ding-Long
authors.initials: DL
authors.lastname: Pan
authors.forename: Zi-Dan
authors.initials: ZD
authors.lastname: Qiu
authors.forename: Ying
authors.initials: Y
authors.lastname: Su
authors.forename: Jian-Ji
authors.initials: JJ
authors.lastname: Pan
mesh_terms: D002448:Cell Adhesion / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects*; D002469:Cell Separation; D002999:Clone Cells; D003114:Colony-Forming Units Assay; D004938:Esophageal Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D005434:Flow Cytometry; D005720:Gamma Rays / Q000009:adverse effects*; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology* / Q000528:radiation effects; D011836:Radiation Tolerance; D014407:Tumor Cells, Cultured
chemical_list: D018960:Hyaluronan Receptors